package com.bzxhh;

public class Test02 {

    public static void main(String[] args) {
        String str = "";
        System.out.println(str.toString()); // ""

        String str1 = null;
        System.out.println(String.valueOf(str1)); //null

        String str2 = null;
        System.out.println(str2.toString()); //java.lang.NullPointerException
    }
}
